Fig. 2
α-Synuclein aggregation and inclusion formation in MSA-exposed TgM83 astrocytes is rapid, gene-dose-, and time-dependent. Quantification of a TgM83+/− and b TgM83+/+ astrocyte cultures exposed to 0.5% brain homogenates from MSA2 (green circles, n = 3), primary passaged MSA2 in TgM83+/− mice (purple circles, n = 3 TgM83+/− astrocytes; n = 6 TgM83+/+ astrocytes), secondary passaged MSA2 in TgM83+/− mice (red circles, n = 6), and age-matched control TgM83+/+ littermates (blue circles, n = 5). Cultures were analyzed at 0, 7, 14, and 21 days post-exposure (dpe). Astrocytes were immunostained for phosphorylated α-synuclein (S129), and the signal intensity was normalized by cell count. We observed a rapid, gene-dose-, and time-dependent accumulation of phosphorylated α-synuclein in astrocytes exposed to MSA prions. Data are plotted with mean and analyzed by one-way ANOVA followed by Tukey’s multicolumn comparison test: ****, P < 0.0001; ***, P = 0.0003. c, d Gene-dose dependency was analyzed by plotting data from (a, b) where TgM83+/+ (black line) and TgM83+/− (grey line) astrocyte cultures were exposed to (c) primary passaged MSA2 (purple circles). Linear regression was applied to each group (TgM83+/+, P = 0.0015; TgM83+/−, P = 0.0496) followed by ANCOVA analysis of covariance to compare the slopes: *, P = 0.0334; F = 10.13; DFn = 1; DFd = 4. d The same Tg mouse lines were exposed to secondary passaged MSA2 (red circles). Linear regression was applied to each group (TgM83+/+, P = 0.0130; TgM83+/−, P = 0.0736) followed by ANCOVA analysis of covariance to compare the slopes: *, P = 0.0411; F = 8.82; DFn = 1; DFd = 4